diff --git a/examples/spawn.c b/examples/spawn.c
index ed1f364..67cfb9c 100644
--- a/examples/spawn.c
+++ b/examples/spawn.c
@@ -18,7 +18,10 @@ int main() {
        local inherited_fds, err = ckb.inherited_fds(); \
        local n, err = ckb.write(inherited_fds[1], m); \
        ckb.close(inherited_fds[1]); \
-       assert(n == 10);",
+       assert(n == 10);\
+       local pid = ckb.process_id(); \
+       assert(pid == 1); \
+        ",
         "hello",
         "world",
     };
diff --git a/lua-loader/lua-ckb.c b/lua-loader/lua-ckb.c
index f1e6f12..4cd53a1 100644
--- a/lua-loader/lua-ckb.c
+++ b/lua-loader/lua-ckb.c
@@ -864,11 +864,49 @@ int lua_ckb_load_header_by_field(lua_State *L) {
 
 // int ckb_wait(uint64_t pid, int8_t* exit_code);
 
-// uint64_t ckb_process_id();
+int lua_ckb_process_id(lua_State *L) {
+    uint64_t pid = ckb_process_id();
+    lua_pushinteger(L, pid);
+    return 1;
+}
 
-// int ckb_pipe(uint64_t fds[2]);
+int lua_ckb_pipe(lua_State *L) {
+    uint64_t fds[2];
+    int err = ckb_pipe(fds);
+    if (err != 0) {
+        lua_pushnil(L);
+        lua_pushinteger(L, err);
+        return 2;
+    }
+    lua_newtable(L);
+    lua_pushinteger(L, fds[0]);
+    lua_rawseti(L, -2, 1);
+    lua_pushinteger(L, fds[1]);
+    lua_rawseti(L, -2, 2);
+    lua_pushnil(L);
+    return 2;
+}
 
-// int ckb_read(uint64_t fd, void* buffer, size_t* length);
+int lua_ckb_read(lua_State *L) {
+    FIELD fields[] = {
+        {"fd", UINT64},
+        {"size", UINT64},
+    };
+    GET_FIELDS_WITH_CHECK(L, fields, 2, 2);
+    uint64_t fd = fields[0].arg.integer;
+    uint64_t size = fields[1].arg.integer;
+
+    uint8_t *buffer = (uint8_t *)malloc(size);
+    int ret = ckb_read(fd, buffer, &size);
+    if (ret != 0) {
+        lua_pushnil(L);
+        lua_pushinteger(L, ret);
+        return 2;
+    }
+    lua_pushlstring(L, (char *)buffer, size);
+    lua_pushnil(L);
+    return 2;
+}
 
 int lua_ckb_write(lua_State *L) {
     FIELD fields[] = {
@@ -917,7 +955,7 @@ int lua_ckb_close(lua_State *L) {
     uint64_t fd = fields[0].arg.integer;
     err = ckb_close(fd);
     lua_pushinteger(L, err);
-    return 2;
+    return 1;
 }
 
 int lua_ckb_load_block_extension(lua_State *L) {
@@ -951,6 +989,9 @@ static const luaL_Reg ckb_syscall[] = {
     {"load_input_by_field", lua_ckb_load_input_by_field},
     {"load_header_by_field", lua_ckb_load_header_by_field},
 
+    {"process_id", lua_ckb_process_id},
+    {"pipe", lua_ckb_pipe},
+    {"read", lua_ckb_read},
     {"write", lua_ckb_write},
     {"inherited_fds", lua_ckb_inherited_fds},
     {"close", lua_ckb_close},